1. Field of the Invention
This invention relates to a circular end-to-end anastomosis stapler apparatus. More particularly, this invention relates to an apparatus for creating a partial circular anastomosis having a novel tissue shielding shroud which is adapted for detachable mounting to the stapler apparatus.
2. Description of the Related Art
Various types of surgical staplers have been known in the past for the application of staples to tissue. For example, it has been known to use various types of staplers in gastric and esophageal surgery, in both classic or modified gastric reconstructions performed end-to-end, end-to-side or side-to-side. In some cases, it has been known to create an anastomosis utilizing an :instrument such as the PREMIUM CEEA.TM. instrument manufactured by United States Surgical Corporation or like instruments where an anvil assembly can be mounted on the end of a central rod which can be retracted within a tubular housing of the instrument. Such an instrument can be introduced into the tureen of a stomach or tubular tissue structure without the anvil in place. Thereafter, the tip of the center rod is passed through an opening which has been made near the anastomotic site so that the anvil can then be mounted on the end of the rod. Subsequently, the anvil can be inserted into the lumen and the end of the lumen tied off, for example, by a purse string suture. Thereafter, the instrument is activated in order to form the staples so as to join the ends of the lumen together. As is known, the instrument can then be removed through the opening originally made in the lumen.
It may be necessary or desirable, however, during certain circular anastomoses to effectuate a less than 360.degree. closure. It is known to mask a potion of an array of staples from engaging tissue. An example of such a device is the subject of U.S. Pat. No. 4,470,533 to Schuler which discloses staple masking means for use with a linear stapling device. It is also known in the art to provide an arcuate or semi-circular array of staples. U.S. Pat. No. 4,617,928 to Alfranca discloses such an array of staples formed by an arcuate staple cartridge and corresponding anvil. Other partial arrays of staples are disclosed in "Experimental Transperitoneal Laparoscopic Pyloroplasty", Surgical Laparoscopy & Endoscopy, Vol. 2, No. 2, June 1992, pp. 104-110. These devices, however, require different size staple cartridges and knives be provided depending on the staple array desired. A need, therefore, still exists for a circular anastomosis stapler capable of performing a partial, i.e., less than 360.degree. anastomosis without requiring additional staple cartridges or knife blades. The novel surgical apparatus according to the present invention obviates the disadvantages encountered in the prior art and provides a precise instrument which is easy to manufacture and efficient to use. The device also eliminates the need for complicated calculation of how many staples are required for the desired completed staple array and fitting the stapling device with the appropriate staple cartridge. Additionally, tissue, not desired to be stapled, is prevented, by the device of the present invention, from entering in between the staple cartridge and the anvil.